Mahut, a 2007 Newport finalist and a wild-card entrant this week, won his second career ATP title.

Mahut lost the longest match in tennis history three years ago, dropping the fifth set to John Isner, 70-68, at Wimbledon in a match that lasted 11 hours, 5 minutes. A display with items used in that match is located a few hundred yards away in the International Tennis Hall of Fame.

On Sunday morning, Mahut advanced after beating Michael Russell, 6-2, 6-2, in just 63 minutes. Mahut needed 2 hours, 19 minutes to get past Hewitt. Then he had to prepare for a doubles semifinal, which he won with Edouard Roger-Vasselin, 6-4, 7-6 (7-4), against Marcelo Demoliner and Andre Sa.

‘‘You guys know I can play a long time, stay a long time on the court,’’ he said, breaking into a grin while standing on a rear practice court.

Earlier in the day, two-time defending champion Isner’s run on Newport’s grass court came to an end when he was ousted by No. 4 seed Hewitt, 5-7, 6-2, 6-4.

The loss ended 13 straight match wins in Newport for the 28-year old Isner, the highest ranked American at No. 19.

Both semifinals were rained out Saturday.

The 6-foot-10-inch Isner said he felt pain in his left knee area, similar to what forced him to retire in his second-round match at Wimbledon.